<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <style>
      @namespace foo "test";
      div { color: green; }
      div[xml|lang="foo"] { color: red; }
      div[xmlns|lang="foo"] { color: red; }
    </style>
  </head>
  <body>
    <div xml:lang="foo">Test</div>
    <div xmlns:lang="foo">Test</div>
  </body>
</html>
